1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
|
/*
Copyright (c) 2015, Synopsys, Inc. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1) Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2) Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
3) Neither the name of the Synopsys, Inc., nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
/* This implementation is optimized for performance. For code size a generic
implementation of this function from newlib/libc/string/strchr.c will be
used. */
#if !defined (__OPTIMIZE_SIZE__) && !defined (PREFER_SIZE_OVER_SPEED)
#include "asm.h"
/* In order to search for a zero in a W, we calculate
X := (W - 0x01010101) & ~W & 0x80808080;
In the little endian case:
If no byte in W is zero, X will be zero; otherwise, the least significant
byte of X which is nonzero indicates the least significant byte of W that
is zero.
In the big endian case:
X will be zero iff no byte in W is zero.
If X is nonzero, to find out which is the most significant zero byte
in W, we calculate:
Y := ~(((W | 0x80808080) - 0x01010101) | W) & 0x80808080;
Each byte in Y is 0x80 if the the corresponding byte in
W is zero, otherwise that byte of Y is 0. */
#if defined (__ARC_BARREL_SHIFTER__) && \
(defined (__ARC600__) || (!defined (__ARC_NORM__) && !defined (__ARC601__)))
ENTRY (strchr)
bmsk.f r2,r0,1
mov_s r3,0x01010101
extb_s r1,r1
asl r5,r1,8
or r5,r5,r1
beq.d .Laligned
asl r4,r5,16
sub_s r0,r0,r2
asl_s r2,r2,3
#ifdef __LITTLE_ENDIAN__
asl r7,r3,r2
#else
lsr r7,r3,r2
#endif
ld_s r2,[r0]
or r5,r5,r4
ror r4,r3
sub r12,r2,r7
bic_s r12,r12,r2
and r12,r12,r4
brne.d r12,0,.Lfound0_ua
xor r6,r2,r5
ld.a r2,[r0,4]
sub r12,r6,r7
bic r12,r12,r6
#ifdef __LITTLE_ENDIAN__
and.f r7,r12,r4
sub r12,r2,r3
bic_s r12,r12,r2
beq.d .Loop
and r12,r12,r4
b.d .Lfound_char_ua
btst r7,7
#else
and.f r8,r12,r4
sub r12,r2,r3
bic_s r12,r12,r2
beq.d .Loop
and r12,r12,r4
bic r12,r7,r6
asl_s r12,r12,7
and.f r2,r8,r12
b.d .Lfound_char_ua
sub_s r0,r0,4
#endif
.balign 4
.Laligned:
ld_s r2,[r0]
or r5,r5,r4
ror r4,r3
sub r12,r2,r3
bic_s r12,r12,r2
and r12,r12,r4
.Loop:
brne.d r12,0,.Lfound0
xor r6,r2,r5
ld.a r2,[r0,4]
sub r12,r6,r3
bic r12,r12,r6
and.f r7,r12,r4
sub r12,r2,r3
bic_s r12,r12,r2
beq.d .Loop
and r12,r12,r4
; Found searched-for character. r0 has already advanced to next word.
#ifdef __LITTLE_ENDIAN__
/* We only need the information about the first matching byte
(i.e. the least significant matching byte) to be exact,
hence there is no problem with carry effects. */
.Lfound_char:
btst r7,7
.Lfound_char_ua:
sub_s r0,r0,4
add.eq r0,r0,1
btst.eq r7,15
add.eq r0,r0,1
btst.eq r7,23
j_s.d [blink]
add.eq r0,r0,1
.balign 4
.Lfound0_ua:
mov_l r3,r7
.Lfound0:
sub r2,r6,r3
bic r2,r2,r6
and r2,r2,r4
or r3,r12,r2
sub_s r12,r3,1
xor_s r3,r3,r12
tst_s r2,r3
lsr r2,r3,31
lsr r12,r3,16
jeq.d [blink]
mov.eq r0,0
lsr r3,r3,8
sub_s r2,r2,r12
sub_s r2,r2,r3
bmsk_s r2,r2,1
j_s.d [blink]
add_s r0,r0,r2
#else /* BIG ENDIAN */
.Lfound_char:
asl r6,r6,7
sub_s r0,r0,4
bic.f r2,r7,r6
.Lfound_char_ua:
add.pl r0,r0,1
jmi.d [blink]
btst_s r2,23
add.eq r0,r0,1
btst.eq r2,15
j_s.d [blink]
add.eq r0,r0,1
; N.B. if we searched for a char zero and found it in the MSB,
; and ignored matches are identical, we will take the early exit
; like for an ordinary found zero - except for the extra stalls at jhi -
; but still compute the right result.
.Lfound0_ua:
mov_s r3,r7
.Lfound0:
asl_s r2,r2,7
or r7,r6,r4
bic_s r12,r12,r2
sub r2,r7,r3
or r2,r2,r6
bic r2,r4,r2
cmp r12,r2
mov.hi r0,0
btst.ls r2,31
jhi.d [blink]
add.eq r0,r0,1
btst.eq r2,23
add.eq r0,r0,1
btst.eq r2,15
j_s.d [blink]
add.eq r0,r0,1
#endif /* ENDIAN */
ENDFUNC (strchr)
#endif /* __ARC_BARREL_SHIFTER__ &&
(__ARC600__ || (!__ARC_NORM__ && !__ARC601__)) */
#endif /* !__OPTIMIZE_SIZE__ && !PREFER_SIZE_OVER_SPEED */
|
